MAPK3 and ischemia: The ERK1/2 pathway is a major pathway stimulated by extracellular hi‐FGF2 and lo‐FGF2.33 The intracrine pathway of ERK1/2 activation is required for hi‐FGF2–triggered chromatin compaction and cell death in HEK293 cells.14 It is important to note that ERK activation may mediate an antiapoptotic function when activated by extracellular FGF2, as exogenous administration of lo‐FGF2 activates the ERK pathway34 and protects the heart from ischemia‐reperfusion–induced myocardial damage.